/*
 * Copyright 2017 Huawei Technologies Co., Ltd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.servicecomb.serviceregistry.config;

import java.util.HashMap;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.netflix.config.DynamicPropertyFactory;

import io.servicecomb.serviceregistry.api.PropertyExtended;

/**
 * 加载微服务和微服务实例的properties
 */
public abstract class AbstractPropertiesLoader {
    private static final Logger LOGGER = LoggerFactory.getLogger(AbstractPropertiesLoader.class);

    protected static final String PROPERTIES = ".properties";

    protected static final String EXTENDED_CLASS = ".propertyExtentedClass";

    protected abstract String getConfigOptionPrefix();

    public Map<String, String> loadProperties() {
        Map<String, String> propertiesMap = new HashMap<>();
        loadPropertiesFromConfigMap(propertiesMap);
        loadPropertiesFromExtendedClass(propertiesMap);

        return propertiesMap;
    }

    protected void loadPropertiesFromConfigMap(Map<String, String> propertiesMap) {
        String configKeyPrefix = mergeStrings(getConfigOptionPrefix(), PROPERTIES);
        propertiesMap.putAll(ConfigurePropertyUtils.getPropertiesWithPrefix(configKeyPrefix));
    }

    protected void loadPropertiesFromExtendedClass(Map<String, String> propertiesMap) {
        String configKey = mergeStrings(getConfigOptionPrefix(), EXTENDED_CLASS);
        String extendedPropertyClass = DynamicPropertyFactory.getInstance()
                .getStringProperty(configKey, "")
                .get();
        if (extendedPropertyClass.isEmpty()) {
            return;
        }
        try {
            Class<?> classExtenalProperty = Class.forName(extendedPropertyClass);
            if (!PropertyExtended.class.isAssignableFrom(classExtenalProperty)) {
                String errMsg = String.format(
                        "Define propertyExtentedClass %s in yaml, but not implement the interface PropertyExtended.",
                        extendedPropertyClass);
                LOGGER.error(errMsg);
                throw new Error(errMsg);
            }

            PropertyExtended instance = (PropertyExtended) classExtenalProperty.newInstance();
            Map<String, String> extendedPropertiesMap = instance.getExtendedProperties();
            if (extendedPropertiesMap != null && !extendedPropertiesMap.isEmpty()) {
                propertiesMap.putAll(extendedPropertiesMap);
            }
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException e) {
            String errMsg = "Fail to create instance of class: " + extendedPropertyClass;
            LOGGER.error(errMsg);
            throw new Error(errMsg, e);
        }
    }

    protected static String mergeStrings(String... strArr) {
        StringBuilder sb = new StringBuilder();
        for (String str : strArr) {
            sb.append(str);
        }
        return sb.toString();
    }

}
